The present invention relates to an apparatus for dispensing sheet material from rolls of sheet material.
It is desirable to provide a sufficient quantity of sheet materials to minimize the frequency of replacing spent rolls. Dispensers capable of storing and dispensing sheet materials from oversize rolls can be effectively used to reduce the frequency of replacing spent rolls. Reducing the frequency of the incidence of encountering spent rolls can be extremely important in high-traffic situations such as, for example, public and institutional washroom facilities.
In the past, dispensers have been designed to store and dispense both metered and unmetered quantities of a sheet material from an oversize roll. However it was found that the weight of the oversize roll frequently caused problems. In some cases, as the sheet material was withdrawn from the roll, the inertia of the rotating heavy roll caused excess sheet material to unwind from the roll. In other cases, the sheet material would prematurely tear due to the inertia of initiating rotation of the heavy roll. The first problem resulted in significant wastage of sheet material whereas the second required frequent user or custodial access to the dispenser to reposition the sheet so that it would feed properly through the dispenser. Such contact between a user and a dispenser can be undesirable, especially in settings such as public rest rooms. Moreover, requiring a custodian to remedy the situation negates some of the reasons to use an oversize roll, that is, to reduce the frequency that a user encounters a spent or inoperative roll as well as to minimize time spent checking and changing rolls.
Generally speaking, it was thought that the disadvantages of using oversize rolls outweighed the advantages. The alternative of using a multi-roll dispenser offered a lot of the same advantages but did not present the same disadvantages as an oversize roll. As a result, industry has generally moved in the direction of using multi-roll dispensers.
Accordingly, there is a need for a simple, inexpensive apparatus for dispensing sheet material from oversize rolls of sheet material which overcomes the negative effects of rotational inertia associated with such a heavy article.
The problems described above are addressed by the present invention which is an apparatus for dispensing sheet material from oversize rolls of sheet material. (However, the apparatus would work equally as well with standard sized rolls.)
Generally speaking, the apparatus includes a drive roller in contact with the circumference of the roll; a feed mechanism; and preferably a housing. The drive roller is in continuous contact with the outer surface or circumference of the roll of sheet material. The roll itself is free to rotate about its axis. Upon operation of the feed mechanism by a user, the drive roller frictionally engages and drives the roll rotationally. This results in the sheet material unwinding from the roll and dispensing through the opening in the housing.
In one embodiment of the present invention, the drive roller may move with respect to the roll of sheet material so that as the sheet material is unwound from the roll, the drive roller moves toward the axis of the roll. This may be accomplished by locating the drive roller at some fixed distance from the feed mechanism. As the roll decreases in circumference, the movement of the drive roller traces an imaginary arc about an axis located at a point on the feed mechanism. The drive roller""s position along this arc is at the same scalar distance from the axis at any moment in time. Since the drive roller is moving arcuately, it can maintain continuous contact with the roll of sheet material. The arrangement described can be created by the use of a bar, rod, arm, or other similar linkage which fixes the scale distance between the drive roller and the point on the feed mechanism.
In an alternative embodiment, the scalar distance between the arbitrary axis on the feed mechanism and the drive roller may vary as well. In this embodiment, an idler such as a pulley, wheel, or gear may be used to keep tension on a belt or band connecting the feed mechanism to the drive roller. As the drive roller moves with respect to the feed mechanism, the idler would move accordingly to keep the belt under sufficient tension to enable the feed mechanism to activate the drive roller.
In either embodiment, it is desirable to maintain sufficient contact between the drive roller and the outer circumference of a continuously diminishing roll of sheet material in such a way that manipulation of the feed mechanism by a user imparts a force to the drive roller which in turn drives the roll via friction.
In yet another embodiment, the apparatus includes the housing, the drive roller in continuous contact with the circumference of the roll; the feed mechanism; and a pivotable arm adapted to receive a roll of sheet material. The drive roller should be in continuous contact with the outer circumference of the roll of sheet material. Desirably, this is accomplished by attaching the roll to the pivotable arm at a distal end of the arm. The roll is free to rotate about its axis. The other end of the pivotable arm is pinned or otherwise pivotally attached to the housing. The weight of the roll of sheet material causes the arm to pivot about its pinned connection until the outer circumference of the roll of sheet material contacts the drive roller. Upon operation of the feed mechanism by the user, the drive roller frictionally engages and drives the roll rotationally about its connection on the pivot arm. This results in the sheet material unwinding from the roll and dispensing through the opening in the housing.
In an aspect of the present invention, the feed mechanism may be a lever connected either directly or indirectly through gears, cables or other appropriate linkages to the drive roller. It is desirable that the lever be operable in only one direction through the use of a one-way clutch or transmission mechanism. Such a mechanism would allow a predetermined quantity of sheet materials to be dispensed by manipulation of the lever, but would not permit the winding or rewinding of sheet materials back onto the roll by manipulation of the lever in the opposing direction.
In another aspect of the invention, a biasing means may be utilized to maintain sufficient contact between the roll of sheet material and the drive roller. Alternatively and/or additionally, the coefficient of friction of the drive roller may be increased by an appropriate selection of materials, surface coatings, and/or surface configurations.
In still another aspect of the invention, a secondary drum may be utilized. The secondary drum may be placed between the drive roller and the opening in the housing so that as the sheet unwinds from the roll, it is made to pass over the secondary drum prior to its being dispensed. Desirably, at or near the end of the dispensing operation, the secondary drum perforates or cuts the sheet material to aid in dispensing.
In another aspect of the invention, the sheet material protruding from the dispenser can be torn from the roll, desirably with the aid of a cutting blade or tear surface located on or within the housing.
In an embodiment of the invention, the housing may be attached to a vertical surface, such as a wall, so that the axis of the roll is perpendicular to the mounting surface. It is desirable to mount the apparatus so that its back wall sits upon the mounting surface. This orientation has the advantage that it minimizes the intrusion of the dispenser into the usable space of the room while maximizing use of wall space which is normally wasted. Alternatively and/or additionally the dispenser may be partially or fully recessed into an opening in the wall.
It is contemplated that turning means can be used to redirect the sheet material as it comes off of the roll so as to dispense the material in any preferred direction if this feature is desirable
In an embodiment of the invention, the pivotable arm may be in a single or double beam configuration. That is, the pivotable arm could be a single arm, desirably located to the rear of the housing to enable easier installation of the roll onto the arm. An appropriate means such as a support bar suitable for maintaining the roll upon the arm would be desirable. The double beam variation includes a rearmost arm and a forwardmost arm. It is envisioned that the roll is placed and maintained between the two arms.
One embodiment does not require the use of an arm of any kind. In this variation, the axis of the roll is engaged with protruding posts, tabs, supports, extensions, or the like which extend into the core of the roll. These posts are slidingly mounted to an interior portion of the housing and allow the roll to slide toward the drive roller until the circumference of the roll comes to rest against the drive roller.
Other embodiments are envisioned. One such embodiment which can be adapted to include any of the features listed above provides a suitable location for accommodating a stub roll. The stub roll could be appropriately dispensed through the opening until the sheet product on the stub roll was completely exhausted at which time additional sheet product would be or would continue to be supplied from the oversize roll accordingly.
A viewing window can be placed in a visually accessible location in the housing to enable a user or custodian to assess the quantity of sheet material on the roll remaining to be dispensed.
According to the invention, the sheet material may be a fibrous cellulosic material. Desirably, the sheet material is paper. More desirably, the sheet material is paper tissue. The sheet material may be wound into a coreless roll. Desirably, the sheet material is wound on a core to form a roll.
It is envisioned that an ultra-high capacity system such as the one presently described would hold at least twice as much sheet material as alternatives currently available. As such, it is contemplated that the apparatus utilize rolls containing at least about 4000 linear feet of paper. For example, rolls containing 2000 through 10,000 linear feet or more may be used. The only limits placed on the size of the roll result from the practical concerns of storage and weight of unused rolls, and dispenser sizes. No physical limits exist with respect to operation of the apparatus concerning the size of the roll. Rolls as large or as small as desired can be utilized satisfactorily in the present apparatus.
To aid especially in the dispensing of particularly thin sheet materials, a set of small nip rolls could be placed between the drive roller and the dispenser opening. It would be desirable for this set of rolls to possess a low friction surface and be pressed together with a low nip force. It would be possible to drive these rolls through the drive roller via gearing, belts, bands, or the like. The surface speed of the rolls should be slightly faster than the surface speed of the drive roller. This would enable the nip rolls to pull the sheet at a slightly greater speed than the sheet is moving at its point of contact with the drive roller.
Since the nip rolls also have a low surface friction and only a slight force between them, the sheet would be constantly slipping in the nip. The advantage of this configuration is that the nip rolls would effectively place the sheet under mild tension which would be helpful in guiding a very light weight or pliable sheet from the drive roll to the discharge opening of the dispenser. It is important to note that these nip rolls could be incorporated into the invention for other purposes.
One of the many advantages of the present invention is that the forces necessary to cause the roll to turn are not transmitted through a discrete length of sheet material as it is unwound from the roll of sheet material. This feature overcomes a number of issues related to the tensile strength of the sheet material which effectively is the limiting factor with other designs on the market. By applying the rotational force to the outer circumference of the roll any rolled material could be unwound regardless of the tensile strength of the sheet, this includes but is not limited to bath tissue and paper towel rolls.
The present invention also overcomes the issue of breaking or stopping the inertia of a spinning roll. Other designs are typically based upon a roll supported on a simple free-spinning hub. Once rotation of this type of roll is started the roll tends to spin until frictional forces stop its motion. This type of uncontrolled free spinning can continue to unwind sheet material from the roll causing jamming of the dispensing mechanism. This new design on the other hand prevents the free-spinning effect by coupling the rotation of the roll of sheet material with the drive roller. The roll thus will turn only when the drive roller is made to rotate.
The present invention also contemplates a method of dispensing sheet material from rolls of sheet material.
The method includes the step of loading and retaining an oversize roll of sheet material into the housing or onto the pivotable arm if the apparatus contains an arm. The pinned portion of the arm allows the arm to pivot downward entirely by or alternatively assisted by gravity until the outer circumference of the roll contacts the drive roller.
Upon operation of the feed mechanism by a user, the drive roller rotates about its axis a predetermined distance. The friction between the drive roller and the outermost length of sheet material on the roll causes the roll to rotate about the axis of the roll on the arm causing the sheet to unwrap from the roll and be fed into a dispensing position. That is, the rotation of the drive roller causes the roll of paper to turn.